A boot-attachment device of a ski, also called ski binding, is designed to secure the skiboot of a skier to a ski. It comprises a front toepiece, also called front end stop, which makes it possible to immobilize the front of the boot and a rear heelpiece of which a jaw interacts with a rear protrusion of the sole of the skiboot. These two attachment elements for attaching a boot are furnished with an automatic disengagement mechanism which makes it possible to release the boot beyond a certain stress, in order to prevent injuries in the event of a fall for example.
Standards define maximum disengagement values that must not be exceeded for the automatic release of a boot in such a secure attachment device. According to the prior art, these disengagements are applied by the toepiece and/or the heelpiece via a mechanical means based on a spring which induces an automatic rotation of the jaws engaged with the boot under the effect of certain forces higher than a certain predefined threshold, in order to release the boot. However, in practice, it occurs that the effect of the disengagement spring alone is insufficient and many statistics show that improved bindings could reduce the number of injuries sustained by skiers. These conventional solutions of mechanical disengagement are notably not very effective in the event of a slow fall of a skier during which the forces transmitted to the attachment elements can remain below the provided disengagement threshold but extend over a long period.